In Diamond/Pearl there are Move Tutors. There a re a few differences though. The first is that your pokemon must be really happy. The second is that they can teach your pokemon
the move unlimited times.

The first Move Tutor is on Route 228. He can teach the moves Frenzy Plant, Blast Burn, & Hydro Cannon. These moves can only be taught the the final forms of all the starters.

The second move tutor can be found on Route 210. She can teach the move Draco Meteor. Draco Meteor is a very strong Dragon type attack that can be taught to any Dragon
type pokemon, as well as Arceus.